Born in Paris, France, Druon was the son of Russian-Jewish[1] immigrant Lazare Kessel (1899-1920)[2] and was brought up at La Croix-Saint-Leufroy in Normandy and educated at the lycée Michelet de Vanves. His father committed suicide in 1920[2] and his mother remarried in 1926; Maurice subsequently took the name of his adoptive father, the lawyer René Druon (1874-1961).

Druon began writing for literary journals at the age of 18. In September 1939, having been called up for military service, he wrote an article for Paris-Soir entitled "J'ai vingt ans et je pars (I am twenty years old and I am leaving)". Following the fall of France in 1940, he was demobilized and remained in the unoccupied zone of France, and his first play, Mégarée, was produced in Monte Carlo in February 1942. He left the same year to join the forces of Charles de Gaulle. Druon became aide de camp to General François d'Astier de La Vigerie.

Druon was elected to the 30th seat of the Académie française on 8 December 1966, succeeding Georges Duhamel. He was elected as “Perpetual Secretary” in 1985, but chose to resign the office in late 1999 due to old age; he successfully pushed for Hélène Carrère d'Encausse to succeed him, the first woman to do so, and was styled Honorary Perpetual Secretary after 2000. On the death of Henri Troyat on 2 March 2007, he became the Dean of the Académie, its longest-serving member.

Druon's only work for children – Tistou les pouces verts – was published in 1957 and translated into English in 1958 (as Tistou of the Green Thumbs) and 2012 (as Tistou: The Boy With Green Thumbs).[10]